A pleated blind for an opening generally comprises a top rail, a bottom rail and a web of a fabric (or other foldable material) arranged between them. The blind is normally arranged so that the fabric is folded in a concertina fashion between the top rail and bottom rail. In use, the bottom rail is displaceable towards and away from the top rail. This in turn causes the folded fabric to be either collapsed or extended. In the pleated blind the fabric is adapted to retain its folds or pleats even when the blind is in an extended condition.
One problem with such an arrangement is that, when the blind is extended, the weight of the fabric will tend to pull the folds or pleats at the top of the blind comparatively straight whilst the folds at the bottom of the blind will remain in close proximity to the bottom rail.
Thus unless the fabric is maintained tensioned between the top and bottom rails it will have a tendency to hang unevenly and otherwise present an unpleasing appearance. Particular problems arise if the blind is not of a regular, rectangular shape. For example, for some applications it may be desirable to employ a pleated blind which is generally triangular or circular. However, such blinds will only conform to the required shape if the pleats are uniformly spaced when the fabric is extended.